I have books with a Series, Series Index and Title in calibre.
I'd like the Series and Index to be included in the title sent to my reading device which is a kindle.

I have a metadata plugboard set up to use:
any format, any device: {series}{series_index:0>2s| | - }{title}
as the title.

This works fine for nearly all my books - but a handful of David Eddings titles are showing only the Title in the kindle.
e.g. "Belgariad 01 - Pawn of Prophecy" just shows up as "Pawn of Prophecy"
When I use Kindle Collections to run a report on books present on the device - all books are correctly reported.
I've tried deleting the books from the device, rebooting the device and then readding them - to no avail.

If I delete and readd two books: one book that does not currently appear correctly and one that does - then both books end up back on the device looking exactly as they did - i.e. the correct one stays correct and the incorrect one is not fixed.

I'm at a loss to understand how this has happened - or how to fix it. From a kindle reset to factory default, all these books were added at the same time so they should have the same behaviour...
Has anyone got any suggestions/ideas?

Just to muddy things further I've found another book that shows up on the kindle as "Untitled", yet when I look in Calibre at the list of books on the device under Device=> Show books in the main memory of the device, I again see the correct title.

So for some reason, the kindle is displaying a different title to what is viewed by calibre -
The title displayed is Untitled - Jack
the only place I can find this info (it's not in calibre) is in the metadata within the mobi where dc:creator = "Jack" and dc:title = "Untitled" - no idea why the kindle is displaying these fields though.